Input interface, portable electronic device and method of producing an input interface

ABSTRACT

An input interface comprises a touch sensor panel having a surface and a first sensor arrangement provided on the surface to sense a position of a touch action with two-dimensional spatial resolution. A transparent window member is offset from the surface of the touch sensor panel in a direction perpendicular to the surface. A second sensor arrangement is interposed between the surface and the transparent window member. The second sensor arrangement is configured to sense a magnitude of a force normal to the surface applied by the touch action and pushing the window member toward the touch sensor panel.

FIELD OF THE INVENTION

The application relates to an input interface, a portable electronicdevice having an input interface, and a method of producing an inputinterface. The application relates in particular to input interfaceswhich include a touch panel sensor configured to sense a touch actionwith two-dimensional spatial resolution.

BACKGROUND OF THE INVENTION

Portable electronic devices provide functionalities which continue to beenhanced. With increasing processing capabilities and functionalitiesprovided in the portable electronic device, it is increasinglychallenging to provide input interfaces which allow the variety offunctionalities to be controlled in an intuitive manner. Touch sensorpanels which sense a touch action enhance the ways in which a user mayinteract with the portable electronic device. Touch sensor panels may beconfigured such that they provide information on the location at which auser touches a window. Touch sensor panels may be configured todiscriminate multi-touch scenarios in which several fingers are used tosimultaneously actuate different regions of the touch sensor panel,and/or to track the movement of a user's finger across the window. Suchdetection capabilities allow different functionalities of the portableelectronic device to be controlled in a way in which the location of oneor plural touch actions, or a movement pattern of the user's fingersacross a window, may encode different control commands. Thetwo-dimensional position(s) of the touch action are the input data whichare evaluated to control operation of the portable electronic device.

One approach to further enhance the operation of the input interface isto derive information on a size of an area at which a user contacts thewindow of the input interface. The size of this area providesinformation on the way in which the user places his or her fingeragainst the window. For illustration, the area over which a touch sensorpanel will be actuated may vary depending on whether the user pushesmore or less strongly against the window, or whether a smaller or largerfinger is placed against the window. While this approach does notrequire a separate sensor and derives additional information from thesize of the area at which the window is touched, it has shortcomings. Itmay be challenging or impossible to discriminate whether a user pushesagainst the window lightly with his index finger or strongly with hislittle finger. When a user places a rigid object, such as a pen-typedevice, against the window, it is inherently difficult to deriveinformation other than the two spatial coordinates defining the positionof the touch action with conventional touch sensors.

SUMMARY

There is a continued need in the art for an input interface, a portableelectronic device and a method of producing an input interface whichaddress some of the above shortcomings. In particular, there is acontinued need in the art for an input interface, a portable electronicdevice and a method of producing an input interface which allowsadditional information on the user's actuation of the touch panel to bederived. There is also a need for such an input interface which can bemanufactured at moderate additional cost.

According to an embodiment, an input interface is provided. The inputinterface comprises a touch sensor panel having a surface and a firstsensor arrangement provided on the surface to sense a position of atouch action with two-dimensional spatial resolution. The inputinterface comprises a transparent window member offset from the surfaceof the touch sensor panel in a direction perpendicular to the surface.The input interface comprises a second sensor arrangement interposedbetween the surface and the transparent window member, the second sensorarrangement being configured to sense a magnitude of a force normal tothe surface applied by the touch action and pushing the window membertoward the touch sensor panel.

The second sensor arrangement may comprise plural conductive tracesarranged on the surface of the touch sensor panel.

The first sensor arrangement may comprise a conductive pattern arrangedon a central area of the surface. The plural conductive traces of thesecond sensor arrangement may be arranged on a peripheral area of thesurface which surrounds the central area.

A spacer area may be formed between the central area and the peripheralarea. The spacer area may extend around the central area.

The first sensor arrangement may comprise other conductive tracesarranged on the central area of the surface. The plural conductivetraces and the other conductive traces may be formed from the samematerial. The plural conductive traces and the other conductive tracesmay be formed simultaneously. The plural conductive traces and the otherconductive traces may be formed in the same printing process.

The input interface may comprise a chip coupled to the conductivepattern to determine the position of the touch action. The chip may befurther coupled to the plural conductive traces to determine themagnitude of the force.

The second sensor arrangement may comprise a force sensing materialinterposed between the surface and the transparent window member, theforce sensing material covering at least two conductive traces of theplural conductive traces. The force sensing material may be applied ontothe surface by printing.

The force sensing material may have a first face contacting the surfaceand a second face contacting the transparent window member. The forcesensing material may bridge the space between the transparent windowmember and the surface of the touch sensor panel.

The first face and the second face may be spaced by a height of theforce sensing material. A transparent material layer may be interposedbetween the conductive pattern and the transparent window member, thetransparent material layer having another height which is less than orequal to the height of the force sensing material. The transparentmaterial layer may be an optical clear adhesive or ultraviolet (UV)curing adhesive.

The force sensing material may be resiliently deformable and may haveelectrical characteristics varying as a function of deformation. Theforce sensing material may have a resistance which varies as a functionof deformation, such that the resistance of the force sensing materialbetween two of the plural conductive traces varies as a function ofapplied force.

The touch sensor panel may have a first side and a second side, thesecond side extending parallel to the first side at a first distance.The transparent window member may have another first side and anothersecond side, the other second side extending parallel to the other firstside at a second distance, the second distance being equal to the firstdistance.

The touch sensor panel may have a third side and a fourth side, thefourth side extending parallel to the third side at a third distance,the third and fourth sides being perpendicular to the first side. Thetransparent window member may have another third side and another fourthside, the other fourth side extending parallel to the other third sideat a fourth distance, the other third and fourth sides beingperpendicular to the other first side, and the fourth distance beingequal to the third distance.

The touch sensor panel may have an outer boundary and the transparentwindow member may have another outer boundary, the other outer boundarybeing flush with the outer boundary. The touch sensor panel and thetransparent window may have identical shapes.

The input interface may further comprise a sealing material interposedbetween the touch sensor panel and the transparent window member. Thesealing material may surround the plural conductive traces of the secondsensor arrangement and the conductive pattern of the first sensorarrangement. The sealing material may be an optical clear adhesive or aUV curing adhesive. The sealing material may form a ring seal.

The transparent window member and the touch sensor panel may extendparallel to each other. The transparent window member and the touchsensor panel may extend at a distance from each other.

According to another embodiment, a portable electronic device isprovided. The portable electronic device comprises a housing having asupport area. The portable electronic device comprises an inputinterface. The input interface comprises a touch sensor panel having asurface and a first sensor arrangement provided on the surface to sensea position of a touch action with two-dimensional spatial resolution.The input interface comprises a transparent window member offset fromthe surface of the touch sensor panel in a direction perpendicular tothe surface. The input interface comprises a second sensor arrangementinterposed between the surface and the transparent window member, thesecond sensor arrangement being configured to sense a magnitude of aforce normal to the surface applied by the touch action and pushing thewindow member toward the touch sensor panel. The touch sensor panel isattached to the support area.

The input interface may be an input interface according to any oneembodiment.

The touch sensor panel may have another surface opposite the surface, anouter boundary of the other surface being fastened to the support area.

The touch sensor panel may be interposed between the transparent windowmember and the support area. The support area may be a shouldersurrounding an opening in the housing of the portable electronic device.

The portable electronic device may further comprise a processing device.The input interface comprises a chip coupled to the conductive patternto determine the position of the touch action, the chip being furthercoupled to plural conductive traces of the second sensor arrangement todetermine the magnitude of the force applied by the touch action. Theprocessing device may be interfaced with the chip and may be configuredto control operation of the portable electronic device as a function ofboth the position of the touch action and the magnitude of the forceapplied by the touch action.

The input interface may comprise a flexible printed circuit on which thechip is arranged, the flexible printed circuit having a connector toprovide the position of the touch action and the magnitude of the forceto the processing device.

According to another embodiment, a method of producing an inputinterface is provided. First conductive traces are formed on a centralarea of a surface of a touch sensor panel to provide a first sensorarrangement. The first sensor arrangement is configured to sense aposition of a touch action with two-dimensional spatial resolution.Second conductive traces are formed on a peripheral area of the surfaceto provide a second sensor arrangement. The second sensor arrangement isconfigured to sense a magnitude of a force applied by the touch action.The peripheral area in which the second conductive traces are formed maysurround the central area of the surface. A force sensing material maybe applied on the second conductive traces. A transparent window membermay be attached to the touch sensor panel such that the transparentwindow member is offset from the touch sensor panel in a directionnormal to the surface and that the second sensor arrangement isinterposed between the touch sensor panel and the transparent windowmember.

The first conductive traces and the second conductive traces may beformed from the same material. The first conductive traces and thesecond conductive traces may be formed simultaneously. The firstconductive traces and the second conductive traces may be formed in thesame printing step.

The force sensing material may be applied by printing. The force sensingmaterial may be resiliently deformable. The force sensing material mayhave electrical characteristics which vary as a function of deformation.

The input interface, portable electronic equipment and method of variousembodiments allow a magnitude of a force to be sensed. The forcemeasurement provides additional information, supplementing the x- andy-coordinates defining the position of the touch actuation. The forcemay be determined even when the user places a rigid object, such as apen-type device, on the transparent window member. The additionalinformation quantifying the magnitude of the force may be used incontrolling operation of a portable electronic device. The ways in whicha user may interact with the portable electronic device may thereby beenhanced, using the force of the touch action as an additional source ofinformation. The operation of the portable electronic device may also becontrolled in an intuitive way, taking into account the strength atwhich a user pushes against the transparent window member.

The costs associated with forming the second sensor arrangement aremoderate. The second sensor arrangement is interposed between the touchsensor panel and the transparent window member. This allows conductivetraces of the second sensor arrangement to be formed efficiently, e.g.in the same processing station in which conductive traces of the firstsensor arrangement are also formed.

It is to be understood that the features mentioned above and featuresyet to be explained below can be used not only in the respectivecombinations indicated, but also in other combinations or in isolation,without departing from the scope of the present invention. Features ofthe above-mentioned aspects and embodiments may be combined with eachother in other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and advantages of the inventionwill become apparent from the following detailed description when readin conjunction with the accompanying drawings, in which like referencenumerals refer to like elements.

FIG. 1 is a front view of a portable electronic device according to anembodiment.

FIG. 2 is a schematic block diagram of the portable electronic device ofFIG. 1.

FIG. 3 is a cross-sectional view through the portable electronic deviceshowing the input interface according to an embodiment in partialcross-sectional view.

FIG. 4 is a detail view of the input interface in cross-sectional view.

FIG. 5 is a plan view of a touch sensor panel of a user interfaceaccording to an embodiment.

FIG. 6 is a perspective view showing the combination of touch sensorpanel and transparent window member of a user interface according to anembodiment.

FIG. 7 is a plan view of a touch sensor panel of a user interfaceaccording to an embodiment.

FIG. 8 is a flow chart of a method performed by a portable electronicdevice according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the invention will be described indetail with reference to the accompanying drawings. It is to beunderstood that the following description of embodiments is not to betaken in a limiting sense. The scope of the invention is not intended tobe limited by the embodiments described hereinafter or by the drawings,which are taken to be illustrative only.

The drawings are to be regarded as being schematic representations, andelements illustrated in the drawings are not necessarily shown to scale.Rather, the various elements are represented such that their functionand general purpose become apparent to a person skilled in the art. Anyconnection or coupling between functional blocks, devices, components orother physical or functional units shown in the drawings or describedherein may also be implemented by an indirect connection or coupling. Acoupling between components may also be established over a wirelessconnection. Functional blocks may be implemented in hardware, firmware,software or a combination thereof. While portable electronic deviceshaving an input interface of an embodiment may be wireless communicationdevices, personal digital assistants, or other portable devices havingcommunication capabilities, the input interface is not limited to beingused in such communication devices.

The features of the various embodiments may be combined with each otherunless specifically noted otherwise.

Portable electronic devices having an input interface will be described.The input interface has a first sensor arrangement to detect a positionof a touch action in a spatially resolved manner. The first sensorarrangement is operative as a touch sensor. The input interfaceadditionally has a second sensor arrangement separate from the firstsensor arrangement and configured to sense a magnitude of a forceapplied by the touch action. The second sensor arrangement is interposedbetween a transparent window member and a touch sensor panel. As will bedescribed in more detail with reference to the drawings, the secondsensor arrangement may have a plurality of conductive traces and aresiliently deformable force sensing material.

FIG. 1 is a front view of a portable electronic device 1 and FIG. 2 is aschematic block diagram representation of the portable electronic device1. The portable electronic device 1 has an input interface 3. The inputinterface 3 includes a first sensor arrangement to sense the position ofa touch action on the input interface, and a second sensor arrangementto sense a force applied by the touch action. The input interface 3 mayinclude a display, thereby implementing a touch-sensitive screen. Theportable electronic device 1 has a processing device 4 coupled to theinput interface 3. The processing device 4 may be one processor or mayinclude plural processors, such as a main processor 11 and a graphicsprocessing unit 12. The processing device 4 may perform processing andcontrol operations. The processing device 4 may be configured such that,at least in some modes of operation, it controls operation of theportable electronic device 1 based on both a position of a touch actionand a force applied by the touch action. The processing device 4 maycontrol operation of the portable electronic device 1 in accordance withinstruction code stored in a memory 5.

The portable electronic device 1 may be operative as a portablecommunication device, e.g. a cellular telephone, a personal digitalassistant, or similar. The portable electronic device 1 may includecomponents for voice communication, which may include a microphone 6, aspeaker 7, and a wireless communication interface 9 for communicationwith a wireless communication network. In addition to the inputinterface 3, the portable electronic device 1 may have separate hardkeys 8, such as function and/or control keys.

With reference to FIG. 3 to FIG. 7, the configuration and operation ofthe input interface 3 will be explained in more detail.

FIG. 3 shows a partial cross-sectional view through the portableelectronic equipment along line III-III in FIG. 1.

The user interface 3 is arranged in an opening of a housing 10 of theportable electronic device 1. The housing 10 may consist of pluralcomponents, such as a first shell 13, a second shell 14, and anintermediate wall 15 which are attached to each other. The first shell13 defines an opening in which the input interface 3 is arranged. At aperiphery of the opening, the first shell 13 has a support area 16. Thesupport area 16 supports the input interface 3. The support area 16 alsoserves as a force support area which provides a counter-force actingonto the input interface 3 when the user presses against the inputinterface 3.

The input interface 3 generally has a touch sensor panel 21 and atransparent window member 22. A surface 30 of the touch sensor panel 21faces toward the transparent window member 22. The transparent windowmember 22 is offset from the surface 30 in a direction perpendicular tothe surface 30. Accordingly, the transparent window member 22 and thetouch sensor panel 21 extend parallel to each other and at a distancefrom each other. On the surface 30, a first sensor arrangement isformed. The first sensor arrangement is configured to sense a positionof a touch action in a spatially resolved manner in two spatialdimensions. The first sensor arrangement may be configured to provideinformation on the x- and y-coordinates at which the user pushes againstthe input interface 3. The first sensor arrangement may be configured asa capacitive or resistive touch sensor, for example.

A second sensor arrangement is arranged on the surface 30. The secondsensor arrangement may include a plurality of conductive traces whichare located on the surface 30. The plurality of conductive traces allowselectrical characteristics of a force sensing material 43 to bemeasured. The force sensing material 43 is interposed between the touchsensor panel 21 and the transparent window member 22. The force sensingmaterial 43 bridges the gap between the touch sensor panel 21 and thetransparent window member 22. The force sensing material 43 may contactboth the touch sensor panel 21 and the transparent window member 22.When the force sensing material 43 is deformed in response to the forceexerted onto the user interface 3, the plurality of conductive tracesallow the resultant change in electrical characteristics to be measured.The magnitude of the force can be derived from the electricalcharacteristics or the change in electrical characteristics. Forillustration, a resistance between a pair of conductive traces of thefirst sensor arrangement may be measured. The resistance may change as afunction of density of the force sensing material 43 which is overlaidon the pair of conductive traces.

The first sensor arrangement is located at a peripheral area of thesurface 30. The plural conductive traces of the second sensorarrangement which are used to measure the magnitude of the force andother conductive traces of the first sensor arrangement may be spatiallyseparated. The plural conductive traces of the second sensor arrangementmay be made from the same material as the other conductive traces of thefirst sensor arrangement. The conductive traces of the first sensorarrangement and the plurality of conductive traces of the second sensorarrangement may be made from silver.

The transparent window member 22 may be attached to the housing 10 viathe touch sensor panel 21. The touch sensor panel 21 may be interposedbetween the transparent window member 22 and the support area 16 atwhich the input interface 3 is attached to the housing 10. The touchsensor panel 21 may be fastened to the support area 16 by an adhesivematerial 24. The adhesive material 24 may be a double adhesive tape, forexample. The adhesive material 24 may be less resilient than the forcesensing material 43. A bulk modulus of the adhesive material 24 may begreater than a bulk modulus of the force sensing material 43.

A transparent layer 25 of material may be arranged between a centralarea of the surface 30 and the transparent window member 22. The layer25 may be made from optical clear adhesive or a UV curing adhesive. Asealing material 26 may be arranged at an outer boundary of the surface30 between the touch sensor panel 21 and the transparent window member22. The sealing material 26 may also be optical clear adhesive or a UVcuring adhesive. The sealing material 26 and the transparent layer 25may be formed simultaneously when the input interface 3 is produced.

The input interface 3 may also include a display 23. The display 23 maybe a liquid crystal display. The display 23 may be attached to the touchsensor panel 21 by an adhesive layer 27. The layer 27 may be made fromoptical clear adhesive or a UV curing adhesive. An air gap 29 may beformed in an interior of the housing adjacent the display 23 between thedisplay 23 and the intermediate member 15. A protective layer 28 may beapplied on an outer surface of the transparent window member 22.

The configuration of the input interface 3 and configurations of thefirst and second sensor arrangements will be described in more detailwith reference to FIG. 4 to FIG. 7.

FIG. 4 shows a portion of the input interface 3 indicated at 19 in FIG.3 as an enlarged partial cross-sectional view.

The first sensor arrangement detects a location at which the inputinterface 3 is actuated. The first sensor arrangement may be configuredas a capacitive touch sensor or as a resistive touch sensor. The firstsensor arrangement includes a conductive pattern 31 which is arranged ona central area of the surface 30. The conductive pattern 31 may bearranged such that it overlays the display 23. The conductive patternmay be a diamond-shaped pattern. The conductive pattern 31 may be formedfrom a transparent material, such as indium tin oxide (ITO), graphene,or another transparent material. Alternatively or additionally, theconductive pattern 31 may be formed such that it does not obstruct thelight emitted from pixels of the display 23. For illustration, theconductive pattern 31 may include thin strips of conductive materialwhich are arranged such that they are located above the boundary ofadjacent pixels of the display 23. The conductive pattern 23 then doesnot have to be formed from a transparent material. The conductivepattern 23 allows light emitted from the display 23 to be seen in avisible area 18 of the input interface.

The first sensor arrangement may include conductive traces 32. Theconductive traces 32 may connect the conductive pattern 31 to anintegrated semiconductor circuit, such as a chip. The conductive traces32 may be arranged in the central area of the surface 30, but may beoffset from a visible area 18 in a direction parallel to the surface 30.The visible area 18 is the area in which the light output by the display23 is transmitted to the user. The layer 25 of transparent material maybe arranged as an overlay of the conductive pattern 31 and theconductive traces 32. The layer 25 may have a height or thickness,measured normal to the surface 30, which is less than or equal to aheight or thickness of the force sensing material 43.

The second sensor arrangement includes a plurality of conductive traces41, 42. More than two conductive traces 41, 42 may be used. Theplurality of conductive traces 41, 42 is formed on the surface 30 of thetouch sensor panel 21. The plurality of conductive traces 41, 42 may beformed in an outer peripheral region of the surface 30. The plurality ofconductive traces 41, 42 may be formed in a region of the surface 30which overlays the support area 16 of the housing.

A force applied to the input interface 3 in a touch action pushes thetransparent window member 22 toward the touch sensor panel 21. Thetransparent window member 22 may be displaced relative to the touchsensor panel 21. Alternatively or additionally, the transparent windowmember 22 and/or the touch sensor panel 21 may deform in response to theapplied force. The resulting displacement or deformation causes theforce sensing material 43 to deform resiliently. A resultant change inelectrical characteristics may be sensed via the plurality of conductivetraces 41, 42. The resultant change allows the magnitude of the force 20to be determined quantitatively.

For illustration rather than limitation, the force sensing material 43may be an ink. The force sensing material 43 may have a resistance whichchanges as the force sensing material 43 becomes compressed. Othermeasurement techniques may be used, such as capacitive sensing which isresponsive to a change in dielectric constant of the material interposedbetween a pair of conductive traces as the force sensing material 43 iscompressed.

The conductive traces 32 of the first sensor arrangement and theplurality of conductive traces 41, 42 of the second sensor arrangementmay be made from the same material. For illustration, the conductivetraces 32 of the first sensor arrangement and the plurality ofconductive traces 41, 42 of the second sensor arrangement may be silverconductive traces. The conductive traces 32 of the first sensorarrangement and the plurality of conductive traces 41, 42 of the secondsensor arrangement may be formed in the same processing step, e.g. whenconductive traces are printed onto the touch sensor panel 21 whenproducing the input interface 3.

The conductive traces 32 of the first sensor arrangement may also bearranged in plural different planes. Some of the conductive traces 32 ofthe first sensor arrangement may be located directly on the surface 30,while some other conductive traces 32 may be located in a plane offsetfrom the surface 30, in between the surface 30 and the transparentwindow member 22. Thereby, a layered structure of conductive traces maybe formed, with the conductive traces 32 of the first sensor arrangementbeing located in different planes and insulating material being arrangedbetween the planes. Alternatively or additionally, the plurality ofconductive traces 41, 42 of the second sensor arrangement may also bearranged in different planes. A layered structure may be formed in whichthe plurality of conductive traces 41, 42 of the second sensorarrangement extends in plural different planes. Insulating material maybe disposed between the planes.

If the conductive traces 32 of the first sensor arrangement and/or theconductive traces 41, 42 of the second sensor arrangement are located indifferent planes, there may be at least one plane in which both someconductive traces 32 of the first sensor arrangement and some conductivetraces 41, 42 of the second sensor arrangement are located. Suchconductive traces lying in the same plane may be formed simultaneously.If there are plural planes in which some conductive traces 32 of thefirst sensor arrangement and some conductive traces 41, 42 of the secondsensor arrangement are located, these conductive traces lying in thesame plane may respectively be formed simultaneously.

Not only the printing of conductive traces 32 of the first sensorarrangement and of conductive traces 41, 42 of the second sensorarrangement may be performed in parallel, but also other processing. Forillustration, if insulating layers are to be applied both on someconductive traces 32 of the first sensor arrangement and on conductivetraces 41, 42 of the second sensor arrangement, the insulating layersmay be applied simultaneously. This allows the second sensor arrangementto be formed in parallel with the first sensor arrangement when theinput interface is produced.

One integrated semiconductor circuit, e.g. one chip, may be used bothfor determining the position of the touch action based on data retrievedusing the first sensor arrangement and the magnitude of the forceapplied by the touch action based on data retrieved using the secondsensor arrangement. The chip of a touch panel sensor may bere-configured so as to perform force measurements using the secondsensor arrangement. The chip may be a touch sensor panel chip which iselectrically connected to the plurality of conductive traces of thesecond sensor arrangement, i.e., of the force sensor. A firmware upgrademay be performed to configure the chip to perform force sensingoperations, in addition to sensing information on a position of a touchaction.

FIG. 5 is a plan view of a touch sensor panel 21 of an input interfaceaccording to an embodiment. The touch sensor panel 21 may be used in theinput interface 3 of the portable electronic device 1 of FIG. 1 and FIG.2.

The surface 30 of the touch sensor panel which faces toward thetransparent window member 22 has a central area 35 on which the firstsensor arrangement for sensing the position of the touch action isprovided. A conductive pattern 31 is formed on a portion 36 of thecentral area 35. The portion 36 with the conductive pattern 31 formedthereon may be overlaid on a display. The conductive pattern 31 may beformed from various conductive materials or combinations of conductivematerials, such as indium tin oxide (ITO), graphene, or other materialssuitable for forming resistive or capacitive touch sensors. Theconductive pattern 31 may extend throughout the portion 36. Theconductive pattern 31 may be a diamond-shaped pattern.

Conductive traces 32 of the first sensor arrangement are located onanother portion 37 of the central area 35. The other portion 37 maysurround the portion 36 on which the conductive pattern 31 is formed.The conductive traces 32 are electrically coupled to the conductivepattern 31 and a chip 51. While only a limited number of conductivetraces 32 are shown, the number of conductive traces 32 of the firstsensor arrangement may be rather large to provide good spatialresolution of position sensing. For illustration, if the conductivepattern 31 includes a first plurality of rows and a second plurality ofcolumns, there may be at least one conductive trace 32 for each row andat least one conductive trace 32 for each column of the conductivepattern 31.

The touch sensor panel 21 extends beyond the central area 35. Theperipheral area 38 of the surface 30 of the touch sensor panel 21extends at an outer side of the central area 35. The peripheral area 38may completely surround the central area 35 to allow force sensing to beperformed at all sides of the input interface. In other implementations,the peripheral area 38 may extend at an outer side of the central area35 only along some of the edges of the touch sensor panel 21.

The peripheral area 38 supports the second sensor arrangement which isconfigured to perform force sensing. The second sensor arrangementcomprises a plurality of conductive traces 41, 42 which are formed onthe peripheral area 38. The plurality conductive traces 41, 42 may beformed externally of the portion 36 overlaid on the display 23. Theconductive traces 41, 42 are then not overlaid on the display 23. Aforce sensing material may be provided to cover at least a pair ofconductive traces 41, 42. The force sensing material may be appliedalong a line which surrounds the central area 35 of the touch sensormaterial. The force sensing material may also be applied locally, e.g.along a portion of the peripheral area 38 which extends along alongitudinal side 61 of the touch sensor panel 21, along another portionof the peripheral edge 38 which extends along transverse side 64 of thetouch sensor panel 21, and/or along another portion of the peripheralarea 38 which extends along the opposite longitudinal side 62.

The plurality of conductive traces 41, 42 of the second sensorarrangement may be connected to the same chip 51 which also evaluatessignals retrieved over the conductive traces 31 of the first sensorarrangement. The chip 51 is an integrated semiconductor circuit whichmay perform operations of both detecting a position of a touch actionand sensing a force magnitude based on signals on the conductive traces41, 42. Other configurations using a dedicated chip for the forcesensing may be used in other embodiments.

The chip 51 is provided on a flexible printed circuit 50. The flexibleprinted circuit 50 also has conductive connections for the force sensingoperation. A connector 52 is formed on the flexible printed circuit 50to interface the chip 51 with the processing device 4 of the portableelectronic device 1 in which the input interface is used. The chip 51may provide information representing the location(s) at which a touchaction occurs to the processing device 4 over the connector 52. The chip51 may additionally provide information representing the magnitude ofthe force applied by the touch action to the processing device 4.

The conductive traces 32 of the first sensor arrangement and theplurality of conductive traces 41, 42 of the second sensor arrangementare both provided on the same surface of the touch sensor panel 21. Thisallows the second sensor arrangement to be formed in a cost-efficientmanner. For illustration, the plurality conductive traces 41, 42 of thesecond sensor arrangement and the conductive traces 31, 32 of the firstsensor arrangement may both be formed by printing. The pluralityconductive traces 41, 42 of the second sensor arrangement and theconductive traces 31, 32 of the first sensor arrangement may be formedin one printing process. The plurality conductive traces 41, 42 of thesecond sensor arrangement and the conductive traces 31, 32 of the firstsensor arrangement may be formed simultaneously. The force sensingmaterial may be applied on the plurality of conductive traces 41, 42 ofthe second sensor arrangement. The force sensing material may be an inkhaving electrical characteristics that vary as a function of density.One example for such a material is an ink with trade name UNEO,available from UCCTW. There is a variety of other resiliently deformablematerials which may be used as force sensing material.

A ring seal made of optical clear adhesive or another sealing material,such as UV curing adhesive, may be applied around the peripheral area38.

The second sensor arrangement which is operative to perform forcesensing is interposed between the touch sensor panel 21 and thetransparent window member 22. The lateral dimensions of the touch sensorpanel 21 may be matched to the lateral dimensions of the transparentwindow member 22. The touch sensor panel 21 may have the same area asthe transparent window member 22.

FIG. 5 and FIG. 6 illustrate dimensions of the touch sensor panel 21 andthe transparent window member 22. Longitudinal sides 61, 62 of the touchsensor panel 21 are spaced by a first distance 65, which corresponds tothe width of the touch sensor panel 21. Longitudinal sides 71, 72 of thetransparent window member 22 are spaced by a second distance 75, whichcorresponds to the width of the transparent window member 22. The firstdistance 65 and the second distance 75 may be equal. I.e., the touchsensor panel 21 and the transparent window member 22 may have identicalwidths.

Alternatively or additionally, the lengths of the touch sensor panel 21and the transparent window member 22 may be matched to one another.Transverse sides 63, 64 of the touch sensor panel 21 are spaced by athird distance 66, which corresponds to the length of the touch sensorpanel 21. Transverse sides 73, 74 of the transparent window member 22are spaced by a fourth distance 76, which corresponds to the length ofthe transparent window member 22. The third distance 66 and the fourthdistance 76 may be equal. I.e., the touch sensor panel 21 and thetransparent window member 22 may have identical lengths.

The touch sensor panel 21 and the transparent window member 22 do notneed to have rectangular shapes. The sizes and shapes of the touchsensor panel 21 and the transparent window member 22 may be matched toone another also when the shape of the touch sensor panel 21 and of thetransparent window member 22 is not rectangular.

The dimensions of the touch sensor panel 21 and of the transparentwindow member 22 do not need to fully coincide. Different shapes and/ordimensions may be used, as long as the second sensor arrangement can beinterposed between the touch sensor panel 21 and the transparent windowmember 22, and the touch sensor panel 21 may be fastened to the supportarea 16 of the housing. In particular, small differences in shapes ofthe outer boundary of the touch sensor panel 21 and of the outerboundary of the transparent window member 22 are tolerable.

The second sensor arrangement may include more than one force sensor toperform force sensing at various locations around the periphery of theinput interface. The force sensing may be performed at locations whichare spaced from the corners of the input interface. The force sensingmay be performed at central regions of the longitudinal and/ortransverse edges of the input interface.

FIG. 7 is a plan view of a touch sensor panel 21 of an input interfaceaccording to an embodiment in which the second sensor arrangement hasseveral force sensors. The touch sensor panel 21 may be used in theinput interface 3 of the portable electronic device 1 of FIG. 1 and FIG.2.

The second sensor arrangement comprises a first force sensor having afirst pair of conductive traces 41, 42 and a force sensing material 43applied thereon. The first force sensor senses a force at a longitudinaledge of the input interface. The second sensor arrangement comprises asecond force sensor having a second pair of conductive traces 44, 45 anda force sensing material 46 applied thereon. The second force sensorsenses a force at an opposite longitudinal edge of the input interface.The second sensor arrangement comprises a third force sensor having athird pair of conductive traces 47, 48 and a force sensing material 49applied thereon. The third force sensor senses a force at a transverseedge of the input interface.

The conductive traces 41, 42, 44, 45, 46 and 47 are all connected to thechip 51. In embodiments, different force sensors may share one of theconductive traces. This conductive trace may correspond to ground, forexample.

Various techniques may be used to derive information on the spatialdistribution of the force acting onto different regions of the inputinterface from the electrical signals sensed over the conductive traces.For illustration, force sensing material having electricalcharacteristics which vary as a function of resilient deformation may beapplied locally in certain regions, to thereby increase the spatialsensitivity of the force sensing. Alternatively or additionally, thedistance between pairs of conductive traces which form a force sensormay be smaller in a region in which the respective force sensor isintended to be sensitive. Distances between conductive traces of thesecond sensor arrangement may therefore vary along the peripheral area38. Alternatively or additionally, even when the force sensing materialis applied on the plurality of conductive traces so as to cover theplurality of conductive traces throughout the peripheral area 38,information on the forces pushing the transparent window member 22toward the touch sensor panel 21 at the various edges of the inputinterface may be derived from calibration data. For illustration, thechip 51 may perform a lookup operation to determine the magnitudes offorces acting at the various edges based on the signals received fromplural force sensors. Information on the position of the touch actiondetermined by the first sensor arrangement may be utilized to derive thedistribution of the forces acting at various edges of the inputinterface.

When the second sensor arrangement has plural force sensors, theoperation of the input interface 3 is enhanced further. Forillustration, the force magnitudes sensed by the plural force sensorsmay be combined with each other to determine the total force.Alternatively or additionally, the force magnitudes sensed by the pluralforce sensors may be used to verify information on a location of a touchaction. Alternatively or additionally, the force magnitudes sensed bythe plural force sensors may be combined with the position informationcaptured using the first sensor arrangement to discriminate differenttypes of touch actions, such as one finger versus plural fingers.

The input interface allows a force magnitude to be captured in additionto information on a position at which a touch action occurs. Operationof the portable electronic device 1 in which the input interface is usedmay be controlled based not only the location of the touch action, butalso based on the force magnitude.

FIG. 8 is a flow chart of a method 80 which may be performed by theprocessing device 4 of the portable electronic device 1 which has theinput interface according to an embodiment.

At 81, it is determined whether there is a touch action at the userinterface. The monitoring at 81 is continued if there is no touchaction. If a touch action is detected, at 82, information on theposition at which the touch action occurs is determined based oninformation captured using the first sensor arrangement which operatesas a touch sensor. The information on the position may include x- andy-coordinates of the touch action. In parallel, at 83 the forcemagnitude is determined based on data captured using the second sensorarrangement which operates as a force sensor.

At 84, the operation of the portable electronic device is controlledbased both on the information on the position and the force magnitude.This may be done in various ways, depending on processes which arepresently being carried out by the portable electronic device. Forillustration, when scrolling through a document, the scroll directionmay be determined based on the x- and y-coordinates of the touch action,while the scroll speed may be set based on the sensed force magnitude.In a shuffle operation, the list of media items in which shuffling isperformed may be selected based on the x- and y-coordinates of the touchaction, while the degree of randomization may be set based on the sensedforce magnitude. In a media player mode, a fast forward or fast rearwardoperation may be selectively performed based on the x- and y-coordinatesof the touch action, while the speed of the fast forward, for example,is set based on the sensed force magnitude. In an operation in which auser sets a number in the portable electronic device, such as time of atimer, the number may be selectively increased or decreased based on thex- and y-coordinates of the touch action, while the increment ordecrement may be determined by the sensed force magnitude. There is awide variety of other scenarios in which the force magnitude providesadditional control functions, which allow the user to control operationof the portable electronic device in an intuitive way.

When the operation of the portable electronic device is controlled basedon the force magnitude, a discretization may be used. For illustration,the sensed force magnitude may be compared to a plurality of forcevalues to determine which action is to be taken.

When the operation of the portable electronic device is controlled basedon the force magnitude, the monitoring of the force may be continuedduring an ongoing touch action. This allows a user to keep a finger orpointing device in engagement with the surface, while controlling theoperation over the force magnitude.

While input interfaces, portable electronic devices and methods havebeen described with reference to the drawings, modifications andalterations may be implemented in further embodiments. For illustration,while the second sensor arrangement operative to sense a force magnitudemay include a pair of conductive traces and a force sensing materialapplied thereon, other implementations of the force sensor are possible.For illustration, the force sensing material may itself include acombination of a resilient insulator with electrically conductivemembers arranged therein at certain heights above the surface of thetouch sensor panel.

For further illustration, while certain implementations of the firstsensor arrangement which detects the position of a touch action weredescribed, other implementations of the first sensor arrangement may beused. For illustration, the conductive pattern may be formed from amaterial other than ITO. A pattern different from a diamond pattern maybe used. The first sensor arrangement may be operative as a resistive orcapacitive touch sensor, for example.

Although the invention has been shown and described with respect tocertain preferred embodiments, equivalents and modifications will occurto others skilled in the art upon the reading and understanding of thespecification. The present invention includes all such equivalents andmodifications and is limited only by the scope of the appended claims.

1. An input interface, comprising: a touch sensor panel having a surfaceand a first sensor arrangement provided on the surface to sense aposition of a touch action with two-dimensional spatial resolution; atransparent window member offset from the surface of the touch sensorpanel in a direction perpendicular to the surface; and a second sensorarrangement interposed between the surface and the transparent windowmember, the second sensor arrangement being configured to sense amagnitude of a force normal to the surface applied by the touch actionand pushing the window member toward the touch sensor panel.
 2. Theinput interface of claim 1, the second sensor arrangement comprisingplural conductive traces arranged on the surface of the touch sensorpanel.
 3. The input interface of claim 2, the first sensor arrangementcomprising a conductive pattern arranged on a central area of thesurface, the plural conductive traces of the second sensor arrangementbeing arranged on a peripheral area of the surface which surrounds thecentral area.
 4. The input interface of claim 3, a spacer area beingformed between the central area and the peripheral area, the spacer areaextending around the central area.
 5. The input interface of claim 3,the first sensor arrangement comprising other conductive traces arrangedon the central area of the surface, the plural conductive traces and theother conductive traces being formed from the same material.
 6. Theinput interface of claim 3, further comprising: a chip coupled to theconductive pattern to determine the position of the touch action, thechip being further coupled to the plural conductive traces to determinethe magnitude of the force.
 7. The input interface of claim 2, thesecond sensor arrangement comprising a force sensing material interposedbetween the surface and the transparent window member, the force sensingmaterial covering at least two conductive traces of the pluralconductive traces.
 8. The input interface of claim 7, the force sensingmaterial having a first face contacting the surface and a second facecontacting the transparent window member.
 9. The input interface ofclaim 8, the first face and the second face being spaced by a height ofthe force sensing material, a transparent material layer beinginterposed between the conductive pattern and the transparent windowmember, the transparent material layer having another height which isless than or equal to the height of the force sensing material.
 10. Theinput interface of claim 7, the force sensing material being resilientlydeformable and having electrical characteristics varying as a functionof deformation.
 11. The input interface of claim 1, the touch sensorpanel having a first side and a second side, the second side extendingparallel to the first side at a first distance, the transparent windowmember having another first side and another second side, the othersecond side extending parallel to the other first side at a seconddistance, the second distance being equal to the first distance.
 12. Theinput interface of claim 11, the touch sensor panel having a third sideand a fourth side, the fourth side extending parallel to the third sideat a third distance, the third and fourth sides being perpendicular tothe first side, the transparent window member having another third sideand another fourth side, the other fourth side extending parallel to theother third side at a fourth distance, the other third and fourth sidesbeing perpendicular to the other first side, the fourth distance beingequal to the third distance.
 13. The input interface of claim 1, thetouch sensor panel having an outer boundary and the transparent windowmember having another outer boundary, the other outer boundary beingflush with the outer boundary.
 14. The input interface of claim 13,further comprising: a sealing material interposed between the touchsensor panel and the transparent window member, the sealing materialsurrounding the surface of the touch sensor panel.
 15. A portableelectronic device, comprising: a housing having a support area; and aninput interface, the input interface comprising: a touch sensor panelhaving a surface and a first sensor arrangement provided on the surfaceto sense a position of a touch action with two-dimensional spatialresolution; a transparent window member offset from the surface of thetouch sensor panel in a direction perpendicular to the surface; and asecond sensor arrangement interposed between the surface and thetransparent window member, the second sensor arrangement beingconfigured to sense a magnitude of a force normal to the surface appliedby the touch action and pushing the window member toward the touchsensor panel; the touch sensor panel being attached to the support area.16. The portable electronic device of claim 15, the touch sensor panelhaving another surface opposite the surface, an outer boundary of theother surface being fastened to the support area.
 17. The portableelectronic device of claim 15, further comprising: a processing device;the input interface comprising a chip coupled to the conductive patternto determine the position of the touch action, the chip being furthercoupled to plural conductive traces of the second sensor arrangement todetermine the magnitude of the force; the processing device beinginterfaced with the chip and being configured to control operation ofthe portable electronic device as a function of both the position of thetouch action and the magnitude of the force.
 18. The portable electronicdevice of claim 17, the input interface comprising a flexible printedcircuit on which the chip is arranged, the flexible printed circuithaving a connector to provide the position of the touch action and themagnitude of the force to the processing device.
 19. A method ofproducing an input interface, the method comprising: forming firstconductive traces on a central area of a surface of a touch sensor panelto provide a first sensor arrangement to sense a position of a touchaction with two-dimensional spatial resolution; forming secondconductive traces on a peripheral area of the surface to provide asecond sensor arrangement to sense a magnitude of a force applied by thetouch action, the peripheral area surrounding the central area of thesurface, applying a force sensing material on the second conductivetraces; and attaching a transparent window member to the touch sensorpanel such that the transparent window member is offset from the touchsensor panel in a direction normal to the surface and that the secondsensor arrangement is interposed between the touch sensor panel and thetransparent window member.
 20. The method of claim 19, the firstconductive traces and the second conductive traces being formed from thesame material, the first conductive traces and the second conductivetraces being formed simultaneously.